This invention concerns the monitoring of the moisture level of hay, and more particularly relates to a specialized sensing device and associated components for the substantially continuous measurement of the moisture level of hay during the baling process.
The moisture level at which hay is baled is critical to the quality of the finished bale. Hay which is baled at a moisture level which is too low (below approximately 10%) shatters during the baling process, causing the leaves to separate from the stems of the plant and pulverize into a fine powder. Hay which is baled at a moisture level which is too high (above approximately 25%) mildews and deteriorates in the bales, resulting in hay which is undesireable as feed. Hay baled at a moisture level above 25% is also susceptible to spontaneous combustion. Hay baled in the 22-25% moisture range tends to turn brown, and is of diminished value as an animal feed.
Various methods of detecting the correct moisture level of hay are available. One method of determining moisture level involves sampling the hay, weighing the sample, drying the sample, weighing the dry sample, and calculating from the two weights the actual moisture level of the sample. This method suffers the disadvantage of being too cumbersome to be practical during the baling operation. In addition, since hundreds of acres of hay may be baled in a single baling session, it is very difficult if not impossible to obtain a representative sample of the hay which is to be baled.
Techniques for measuring the moisture content of hay based upon the direct relationship of electrical conductivity to moisture content are well known. In some such techniques, a sample of hay is placed in the test compartment of an instrument which measures electrical conductivity. In other variations, an elongated probe having two electrodes in its tip is caused to penetrate a bale to provide conductivity readings of interior regions of the bale.
Like the drying and weighing method, earlier conductivity-measuring techniques have the shortcoming of being a batchwise test. Since thousands of bales may be made in one baling session, it is nearly impossible to secure by batchwise test methods truly representative sampling and evaluation of all the hay passing through the baler.
Conventional hay baler machines are generally comprised of: (a) a driver's compartment, (b) a feeder mechanism which picks the hay up from the ground, (c) a section which distributes the hay to form a relatively uniform stream, (d) a forming chamber wherein the stream is compacted to a desired density, producing a tied bundle, and (e) a squeeze rail region where the bundle is further compacted to form the finished bale which is discharged onto the ground. The forming chamber and squeeze rail region, which may be generically characterized as compression zones, have flat retaining walls against which the hay slides as it advances through the baler. The hay will generally pass through said compression zones at a linear flow velocity of between about 150 and 500 inches per minute. The flow is substantially continuous, although having in certain instances a uniformly pulsed motion caused by the compacting mechanisms.
It is accordingly an object of this invention to provide a sensing device as a component of a moisture monitoring system which is continuous in nature and which is directly associated with the baler such that every bale which is baled may be checked for moisture content.
It is a further object of this invention to provide a method utilizing a system as in the foregoing object which determines moisture level of hay during the baling process so that the bailing process can be halted when the moisture content of the hay is outside acceptable limits.
It is a still further object of the present invention to provide a system of the aforesaid nature comprised of apparatus components of rugged, durable construction capable of withstanding the corrosive, abrasive conditions prevalent within a hay baler.
It is yet another object of the invention to provide apparatus of the aforesaid nature amenable to low cost manufacture and facile installation into conventional hay baling equipment.
These objects and other objects and advantages of the invention will be apparent from the following description.